At Least 12 Month Intervals Between Pregnancies Saves Infant Lives

CINCINNATI – A new study finds that dozens of infant lives would be saved in Ohio each year if women would maintain an interval between pregnancies of at least 12 months.

The researchers suggest that 31 infant mortalities could have been prevented each year during the study period between Jan. 2007 and Sept. 2014, and the infant mortality rate reduced from 7.2 per 1,000 live births to 7 per 1,000 live births during the same time frame. 

"An interpregnancy interval of 12 months to five years between birth and conception of next pregnancy is associated with the lowest risk of infant mortality,” says corresponding author Emily DeFranco, DO, associate professor in the Department of Obstetrics and Gynecology at the UC College of Medicine, and a physician-researcher at Cincinnati Children’s Hospital Medical Center. "Public health initiatives and provider counseling to optimize birth spacing have the potential to significantly reduce infant mortality for both white and black mothers.”

The infant mortality rate in Ohio is above the national average, and the black infant mortality rate is more than twice the white infant mortality rate.  During the time period of this study, when the infant mortality rate was 7.2, for white mothers in Ohio it was 6 and for black mothers it was 13.1.

Infant mortalities occurred more often (9.2 per 1,000) for births that occurred following intervals of 0 to less than 6 months and 7.1 per 1,000 for intervals between 6 and less than 12 months. This compared to 5.6 per 1,000 for intervals between 12 and less than 24 months. The highest risk for infant mortality followed intervals between pregnancies of 0 to less than 6 months, with nearly one of four falling in this time span.  The risk following intervals between 6 and less than 12 months was 14 percent.

"By avoiding short, interpregnancy intervals of 12 month or less, we estimate that in the state of Ohio, 20 white and eight black infant mortality deaths could have been prevented,” says David McKinney, MD, a fellow in the Department of Obstetrics and Gynecology, and lead author of the study.

The researchers studied Ohio birth and infant death records. During the study period, 3,701 infant mortalities were linked to a live birth certificate with an interpregnancy interval available. The researchers calculated the frequency and relative risk of infant mortality for various intervals. Short intervals were common, with 20.5 percent of all births following an interval of less than 12 months.

The study is published online in the American Journal of Obstetrics & Gynecology.

The study was supported by the Perinatal Institute at Cincinnati Children’s, and a grant (22-FY14-470) from the March of Dimes Prematurity Research Center Ohio Collaborative.